1. Field of the Invention
This invention relates generally to absorbent articles such as pantiliners and, more particularly, to absorbent articles which permit the passage of vapor while retaining and retarding the passage of fluids.
2. Background Art
Absorbent articles such as sanitary napkins and pantiliners are well known for their use in absorbing and retaining liquid discharges from the human body. Sanitary napkins are used principally during a woman's menstrual period to contain menses and other vaginal discharges so as to protect garments from soiling. However, many women experience frequent or daily, light vaginal discharges between their menstrual periods. While sanitary napkins are an efficient way to deal with the problem, products such as pantiliners have been developed specifically to protect a woman's garments from soiling due to these light discharges and to provide supplemental protection for garments when other catamenial products are used during the menstrual period.
Pantiliners are generally small in size, absorbent and comfortable to use. Several references describe the use of such pantiliners. Generally, pantiliners are intended to be affixed to the crotch region of the user's undergarment and comprise an absorbent core, a topsheet, and an impermeable backsheet located on the pantiliner's garment-facing side that acts as a fluid barrier to absorbed body liquids so as to protect the user's garments from staining. For example, U.S. Pat. No. 3,463,154 issued to Hendricks on Aug. 26, 1969, discloses a disposable panty shield for undergarments which has an outer liquid repellent layer made from a plurality of thin sheets of vinyl or polyethylene to retain the liquid within the shield. U.S. Pat. No. 2,964,040 issued to Ashton et al. on Dec. 13, 1960, discloses an arcuate shaped pad with a water repellent layer to prevent liquid strikethrough of absorbed body fluids.
Because pantiliners are used for daily, light vaginal discharges, generally they are designed to be worn all day. However, because of the impermeable backsheet, conventional pantiliners can be hot and uncomfortable to wear for long periods of time. In addition, the impermeability of the backsheet precludes the pantiliner from self-drying which would otherwise occur through evaporation of the absorbed liquid.
Several absorbent devices have been developed which are pervious to vapor. Products which are pervious to vapor are generally known as "breathable". For example, U.S. Pat. No. 4,341,216 issued to Obenour on July 27, 1982, discloses a breathable backsheet constructed of a vapor pervious and liquid impervious outer sheet and a smaller length liquid impermeable inner sheet. U.S. Pat. No. 3,426,754 issued to Bierenbaum et al. on Feb. 11, 1969, discusses a breathable medical dressing constructed from a microporous polymer film.
Pantiliners are also known which provide a breathable backsheet. Generally, these pantiliners are provided with a fluid impervious, vapor permeable backsheet to allow the exchange of vapor while preventing the staining of the wearer's undergarment. For example, U.S. Pat. No. 4,059,114 issued to Richards on Nov. 22, 1977, discloses a disposable garment shield having a moisture barrier ply constructed of a blown microfiber web which is fluid impermeable but vapor permeable. European Patent Application No. 0 104 906 filed by Becker et al. on Sept. 23, 1983, and published Apr. 4, 1984, discusses a breathable panty liner having a fibrous, vapor permeable, liquid repellent outer layer.
While these "breathable" pantiliners do provide some measure of improvement over the more common "impermeable" pantiliners, comfort, garment staining, dryness, and vapor exchange (breathability) remain as key design considerations. Accordingly, devices providing for the better retention and absorption of liquids while providing for the more efficient passage of vapor have been sought.
It is, therefore, an object of the present invention to provide a "breathable" pantiliner.
It is a further object of this invention to provide a pantiliner with ventilation areas which allow the exchange of vapor thereby providing cooling and drying effects so that the pantiliner is more comfortable to wear.
It is a further object of this invention to provide a pantiliner which prevents fluid leakage from the most common areas of pantiliner soiling to protect the wearer's garments, while maintaining its ability to allow the exchange of vapor.
Other objects and advantages of the present invention will be apparent to one skilled in the art from the following description.